Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a first embodiment of a display screen orportion thereof with transitional graphical user interface according tothe claimed design;

FIG. 2 is a front view of a second image thereof; and,

FIG. 3 is a front view of a third image thereof.

The appearance of the transition is sequential from FIG. 1 to FIG. 2 toFIG. 3. The process or period in which an image transitions to anotherimage forms no part of the claimed design.

The longer-incremented broken-lines showing a portion of an electronicdevice and the intermediate-length broken-lines showing a display screenboundary, as well as the still shorter broken-lines showing unclaimedfeatures, are included for the purpose of illustrating environmentalstructure and form no part of the claimed design.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.